The invention relates to a pedal, in particular for a vehicle, having a pedal arm which is mounted in a retaining part such that it can be pivoted about a pivot axis and which can be deflected, by means of a pedal plate, by way of foot force and can be pivoted back into an initial position by at least one restoring-spring element, and having a friction damper which comprises a friction body and a friction surface and is intended for damping the movement of the pedal arm, the friction body being connected to the pedal arm and being prestressed against the friction surface by means of the restoring-spring element.
Such pedals are commonly used nowadays as gas pedals in motor vehicles and are thus known. Upon actuation of the pedal arm, the friction body slides over the friction surface and thus prevents slight changes in the foot force on the pedal arm, for example caused unintentionally by reactions of the vehicle movement, from resulting in a change in the pedal position. In this case, the friction produced in the friction damper is usually greater in the actuating direction of the pedal arm than in the opposite direction. As a result, the friction damper has a hysteresis which ensures that the pedal arm pivots reliably back into an initial position.
The pedal arm bears at least one friction body, which is in the form of a segment of a circle and rests against a friction surface arranged at one free end of a two-armed lever. At the same time, the pedal arm is connected to the other end of the lever by means of a compression spring. This means that the contact-pressure force between the friction body and friction surface increases as the deflection of the pedal arm increases, with the result that the damping is enhanced. As a result of the abovedescribed design, the pedal requires a larger number of components which, for production and fitting, involve high outlay, the amount of space required by the arrangement, at the same time, being relatively large.
The object of the invention is to configure a pedal of the type mentioned in the introduction such that it is of as straightforward a construction as possible and, at the same time, requires just a small amount of space.
This problem is solved according to the invention in that the friction body is arranged eccentrically with respect to the pivot axis. As a result, the increase in friction, in the event of a large deflection about the pivot axis, is determined not by the restoring-spring element but, in particular, by the eccentricity of the friction body. The friction body, in this case, permits virtually any desired shaping and, associated therewith, any desired movement characteristics of the pedal arm. At the same time, it is also possible, by way of the shaping of the friction body, for the restoring force, counter to the pedal movement, to be such that adaptation to a desired characteristic curve is possible without any special restoring-spring element being necessary for this purpose.
The invention also permits the use a of conventional restoring-spring element. The pedal is designed in a particularly compact manner, according to the present invention, if the restoring-spring element is designed as a leg spring or leaf spring. This advantageously dispenses with the otherwise necessary lever, with the result that the friction body is positioned directly against the restoring-spring element.
A particularly advantageous development of the invention is one in which the friction body is designed as a cam plate. As a result, the pedal-actuating force which is to be applied by the user can be adapted optimally to desired characteristics. In particular, it is possible to combine in stepless fashion regions of the deflection action of the pedal arm with a greatly increased resistance and regions with a low resistance. For example, it is possible to represent progressive regions, in which the output limits of the drive are indicated to the driver as a greatly increased resistance.
A further advantageous embodiment of the invention is achieved if the friction body is designed with point symmetry and is clamped in between the legs of a leg spring. As a result, the spring forces applied on the friction body by the two legs of the leg spring in each case are approximately of the same magnitude and act in more or less mutually opposite directions. Only very small forces thus act on the mount of the leg spring, as a result of which the pedal can be of particularly straightforward design.
The invention is of particularly cost-effective design if, on its side which is directed toward the friction body, the restoring-spring element is designed as a friction surface. This dispenses with the laborious operation of providing a separate friction surface on the elastic restoring-spring element. At the same time, one operation in the fitting process is done away with, this rendering said design particularly cost-effective.
A particularly straightforward development of the invention is achieved if the friction body is an eccentric cam. The design merely requires extremely low production outlay and facilitates adaptation of conventional pedals in accordance with the present invention. At the same time, particularly space-saving configurations are possible with this embodiment.
A further advantageous embodiment of the invention is achieved if the restoring-spring element has a progressive spring characteristic. This further assists the function of the eccentric arrangement of the friction body. At the same time, particularly finely tuned and precise coordination with predetermined movement characteristics can be achieved.